Above- and below-ground methane fluxes and methanotrophic activity in a landfill-cover soil.

Landfills are a major anthropogenic source of the greenhouse gas methane (CH(4)). However, much of the CH(4) produced during the anaerobic degradation of organic waste is consumed by methanotrophic microorganisms during passage through the landfill-cover soil. On a section of a closed landfill near Liestal, Switzerland, we performed experiments to compare CH(4) fluxes obtained by different methods at or above the cover-soil surface with below-ground fluxes, and to link methanotrophic activity to estimates of CH(4) ingress (loading) from the waste body at selected locations. Fluxes of CH(4) into or out of the cover soil were quantified by eddy-covariance and static flux-chamber measurements. In addition, CH(4) concentrations at the soil surface were monitored using a field-portable FID detector. Near-surface CH(4) fluxes and CH(4) loading were estimated from soil-gas concentration profiles in conjunction with radon measurements, and gas push-pull tests (GPPTs) were performed to quantify rates of microbial CH(4) oxidation. Eddy-covariance measurements yielded by far the largest and probably most representative estimates of overall CH(4) emissions from the test section (daily mean up to ∼91,500µmolm(-2)d(-1)), whereas flux-chamber measurements and CH(4) concentration profiles indicated that at the majority of locations the cover soil was a net sink for atmospheric CH(4) (uptake up to -380µmolm(-2)d(-1)) during the experimental period. Methane concentration profiles also indicated strong variability in CH(4) loading over short distances in the cover soil, while potential methanotrophic activity derived from GPPTs was high (v(max)∼13mmolL(-1)(soil air)h(-1)) at a location with substantial CH(4) loading. Our results provide a basis to assess spatial and temporal variability of CH(4) dynamics in the complex terrain of a landfill-cover soil.

Aplasia cutis congenita--plastic reconstruction of three scalp and skull defects with two opposed scalp rotation flaps and split thickness skin grafting.

Aplasia cutis congenita (ACC) is a rare congenital defect of skin and subcutaneous tissue, more rarely of periosteum, skull and dura. The lesions can involve any location, but most common are scalp defects. We report on the successful treatment of three large defects of the scalp with skull involvement in a newborn girl by early debridement and defect closure with two opposed scalp rotation flaps and an occipital split-thickness skin graft.

Quantifying methane oxidation in a landfill-cover soil by gas push-pull tests.

Methane (CH(4)) oxidation by aerobic methanotrophs in landfill-cover soils decreases emissions of landfill-produced CH(4) to the atmosphere. To quantify in situ rates of CH(4) oxidation we performed five gas push-pull tests (GPPTs) at each of two locations in the cover soil of the Lindenstock landfill (Liestal, Switzerland) over a 4 week period. GPPTs consist of the injection of a gas mixture containing CH(4), O(2) and noble gas tracers followed by extraction from the same location. Quantification of first-order rate constants was based upon comparison of breakthrough curves of CH(4) with either Ar or CH(4) itself from a subsequent inactive GPPT containing acetylene as an inhibitor of CH(4) oxidation. The maximum calculated first-order rate constant was 24.8+/-0.8 h(-1) at location 1 and 18.9+/-0.6 h(-1) at location 2. In general, location 2 had higher background CH(4) concentrations in vertical profile samples than location 1. High background CH(4) concentrations in the cover soil during some experiments adversely affected GPPT breakthrough curves and data interpretation. Real-time PCR verified the presence of a large population of methanotrophs at the two GPPT locations and comparison of stable carbon isotope fractionation of CH(4) in an active GPPT and a subsequent inactive GPPT confirmed that microbial activity was responsible for the CH(4) oxidation. The GPPT was shown to be a useful tool to reproducibly estimate in situ rates of CH(4) oxidation in a landfill-cover soil when background CH(4) concentrations were low.

Very early extubation after open-heart surgery in children does not influence cardiac function.

The objective of our study was to evaluate hemodynamic effects and the cardiac function after very early extubation within the first 6 hours after open-heart surgery in children. During a 12-month period, we performed a retrospective study of 50 children (ages 3 months to 7 years) admitted to the pediatric intensive care unit immediately after minor cardiac surgery. All children were extubated within the first 6 hours after their arrival. Arterial blood and central venous pressure were monitored, and arterial blood gas analysis was performed. Cardiac index, stroke volume index, systemic vascular resistance index, and extravascular lung water index were measured by thermodilution. Early extubation of children after minor open-heart surgery with cardiopulmonary bypass is safe and does not affect cardiac functions. A slight decrease of arterial oxygen tension not resulting in respiratory or metabolic acidosis or reintubation was noted. Very early extubation in children after open-heart surgery does not promote cardiodepressive effects. It is a safe procedure that helps to reduce the unnecessary and prolonged mechanical ventilation of children after cardiopulmonary bypass surgery.

Plasmatic [corrected] factor XIII reduces severe pleural effusion in children after open-heart surgery.

Chylous effusions frequently occur after cardiac surgery due to severe damage to the lymphatic system, thus indicating that the insertion of a chest tube may be necessary. Factor XIII (FXIII) is discussed as being essential for wound healing. The aim of this retrospective study was to evaluate whether the application of a single dose of FXIII results in a reduced amount of pleural effusion, leading to an earlier release of patients from the hospital. The cases of 40 children with severe chylous effusions after open-heart surgery were examined. Twenty patients received FXIII and were compared to 20 age- and weight-matched patients who did not receive FXIII. Major parameters included the amount of effusion before and 1 and 3 days after the application of FXIII; the duration of chest tubes; the total amount of fluid loss via drainage; and the period of hospitalization. FXIII levels in plasma showed an inverse correlation with fluid loss. After application of a single dose of FXIII, a significant reduction of pleural effusion within the first 24 hours was detected. However, no difference was observed between the two groups when comparing the total amount of pleural effusions within the first 72 hours. Finally, the duration of hospitalization did not differ between the FXIII-treated and the control group. A single application of FXIII rapidly reduces the amount of chylous effusions in the early period after open-heart surgery. This effect is detectable only for 24 hours after the treatment and does not alter the further clinical outcome. Prospective clinical trials are warranted to determine if repeated application or a higher dose of FXIII may improve the clinical outcome of chylous leakages in children after open-heart surgery.

[Patients with ornithine transcarbamylase deficiency. Anaesthesiological and intensive care management]. / Der Patient mit Ornithintranscarbamylasemangel. Anästhesiologisches und intensivmedizinisches Management.

Ornithine transcarbamylase deficiency (OTCD) is the most common inborn urea cycle disorder. Patients with OTCD are at risk of acute metabolic decompensation with hyperammonemia and subsequent encephalopathy, coma and death. Symptoms may be triggered by infections, drugs and stress, evoked by trauma, pain, fear, surgery and anaesthesia or by episodes of protein catabolism, i.e. fasting-induced, post partum or during gastrointestinal bleeding. Several specific considerations must be made for anaesthetic and intensive care management in patients with this disease in order to avoid metabolic decompensation. We report the intensive care management of the first manifestation of late-onset OTCD in a 16-year-old girl and a course of inconspicuous general anaesthesia with midazolam, s-ketamine, fentanyl and isoflurane in a 22-year-old girl with known OTCD.

Prediction of depth of sedation and anaesthesia by the Narcotrend EEG monitor.

BACKGROUND: The Narcotrend (Monitor Technik, Bad Bramstedt, Germany) assesses sedation by automatic classification of EEG signals, using a scale first used for visual evaluation of the EEG. Limited information is available on its value, and only a few studies of the method exist. We set out to study the performance of the Narcotrend during propofol sedation. METHODS: In 23 ASA I-II patients, aged 18-65 yr, about to have general anaesthesia, we induced anaesthesia in steps using a target-controlled infusion of propofol. After equilibration for 8 min at each predicted propofol concentration (0.5, 1.0, 2.0, 3.0 and 4.0 microg x ml(-1)), sedation was assessed clinically with the modified Observer's Assessment of Alertness/Sedation Scale and the Narcotrend stage was noted. The prediction performance of the Narcotrend was assessed with the prediction probability P(K). A P(K) value of 1.0 means an exact prediction on every occasion, while a P(K) of 0.5 is no better than a 50:50 chance of being correct. RESULTS: In 12 women and 11 men (age 42 (sd 11) yr), a total of 138 measurements were made; 129 were analysed and nine were of poor signal quality. The prediction probability for the corresponding level of sedation was P(K)=0.92 (se 0.01); for the different target concentrations of propofol it was P(K) = 0.91 (se 0.01). CONCLUSIONS: The Narcotrend can monitor sedation with propofol. Other sedatives, anaesthetics and opioids should be used to test this monitor.

Nitrate-consuming processes in a petroleum-contaminated aquifer quantified using push-pull tests combined with 15N isotope and acetylene-inhibition methods.

Nitrate consumption in aquifers may result from several biogenic and abiotic processes such as denitrification, assimilatory NO3- reduction, dissimilatory NO3- reduction to ammonium (DNRA), or abiotic NO3- (or NO2-) reduction. The objectives of this study were to investigate the fate of NO3- in a petroleum-contaminated aquifer, and to assess the feasibility of using single-well push-pull tests (PPTs) in combination with 15N isotope and C2H2 inhibition methods for the quantification of processes contributing to NO3- consumption. Three consecutive PPTs were performed in a monitoring well of a heating oil-contaminated aquifer in Erlen, Switzerland. For each test, we injected 500 l of test solution containing 0.5 mM Br- as conservative tracer and either 0.5 mM unlabeled NO3- or approximately 0.3 mM 15N-labeled NO3- as reactant. Test solutions were sparged during preparation and injection with either N2, Ar or 10% C2H2 in Ar. After an initial incubation period of 1.5-3.2 h, we extracted the test solution/groundwater mixtures from the same location and measured concentrations of relevant species including Br-, NO3-, NO2-, N2O, N2, and NH4+. In addition, we determined the 15N contents of N2, N2O, NH4+, and suspended biomass from 15N/14N isotope-ratio measurements. Average total test duration was 50.5 h. First-order rate coefficients (k) were computed from measured NO3- consumption, N2-15N production and N2O-15N production. From measured NO3- consumption we obtained nearly identical estimates of k for all PPTs with small 95% confidence intervals, indicating good reproducibility and accuracy for the tests. Estimates of k from N2-15N production and N2O-15N production indicated that denitrification accounted for only 46-49% of observed NO3- consumption. Production of N2-15N in the presence of C2H2 was observed during one of the tests, which may be an indicator for abiotic NO3- reduction. Moreover, 15N isotope analyses confirmed occurrence of assimilatory NO3- reduction (0.58 at.% 15N in suspended biomass) and to a smaller extent DNRA (up to 4 at.% 15N in NH4+). Our results indicated that the combination of PPTs, 15N-isotope and C2H2 inhibition methods provided improved information on denitrification as well as alternative fates of NO3- in this aquifer.

Hypercalcemia and idiopathic hypoparathyroidism.

Idiopathic primary hypoparathyroidism (prHP) is a rare disorder and clinical experience of its management is limited. Prolonged immobilization of such patients can cause hypercalcemia and hypercalciuria. We report on a boy with prHP who developed hypercalcemia and renal failure as a result of calcium and calcitriol substitution not being stopped while he was immobilized for 2 months. Any substitution in patients with prHP must be stopped during prolonged immobilization. Laboratory monitoring is mandatory during this period.

Renal loss of leptin in patients with nephrotic syndrome.

OBJECTIVE: In humans, short term changes of serum leptin lead to alterations in food intake and energy expenditure. The objective of the present study was to relate urine leptin concentrations with the extent of proteinuria in patients with nephrotic syndrome (NS). A second goal was to investigate the impact of potential urinary leptin losses on serum leptin concentrations and body composition. DESIGN AND METHODS: Seventeen patients with proteinuria were compared with twenty patients with remission of NS and ten healthy children. Leptin was measured by radioimmunoassay. RESULTS: Urinary leptin excretion in proteinuric patients was significantly higher than in non-proteinuric patients with and without NS and in healthy controls (2.64+/-0.034 microg/g creatinine, 0.026+/-0.05 microg/g creatinine, and 0.073+/-0.11 microg/g creatinine respectively; P<0.001 and P<0.01 respectively compared with controls). Urine leptin positively correlated with urine IgG concentration (P=0.013, r2=0.36) in the proteinuric group. No difference in serum leptin values could be demonstrated between the three groups. CONCLUSIONS: In summary, our data demonstrate a significant leptin excretion in children with severe proteinuria. Proteinuria, however, does not lead to changes in serum leptin, suggesting that the significant loss of leptin is compensated for by sustained up-regulation of leptin production.

In situ assessment of microbial sulfate reduction in a petroleum-contaminated aquifer using push-pull tests and stable sulfur isotope analyses.

Anaerobic microbial activities such as sulfate reduction are important for the degradation of petroleum hydrocarbons (PHC) in contaminated aquifers. The objective of this study was to evaluate the feasibility of single-well push-pull tests in combination with stable sulfur isotope analyses for the in situ quantification of microbial sulfate reduction. A series of push-pull tests was performed in an existing monitoring well of a PHC-contaminated aquifer in Studen (Switzerland). Sulfate transport behavior was evaluated in a first test. In three subsequent tests, we injected anoxic test solutions (up to 1000 l), which contained 0.5 mM bromide (Br-) as conservative tracer and 1 mM sulfate (SO4(2-)) as reactant. After an initial incubation period of 42.5 to 67.9 h, up to 1100 l of test solution/groundwater mixture was extracted in each test from the same location. During the extraction phases, we measured concentrations of relevant species including Br-, SO4(2-) and sulfide (S(-II)), as well as stable sulfur isotope ratios (delta 34S) of extracted, unconsumed SO4(2-) and extracted S(-II). Results indicated sulfate reduction activity in the vicinity of the test well. Computed first-order rate coefficients for sulfate reduction ranged from 0.043 +/- 0.013 to 0.130 +/- 0.015 day-1. Isotope enrichment factors (epsilon) computed from sulfur isotope fractionation of extracted, unconsumed SO4(2-) ranged from 20.2 +/- 5.5@1000 to 22.8 +/- 3.4@1000. Together with observed fractionation in extracted S(-II), isotope enrichment factors provided strong evidence for microbially mediated sulfate reduction. Thus, push-pull tests combined with stable sulfur isotope analyses proved useful for the in situ quantification of microbial sulfate reduction in a PHC-contaminated aquifer.

In-situ oxidation of trichloroethene by permanganate: effects on porous medium hydraulic properties.

In-situ oxidation of dense nonaqueous-phase liquids (DNAPLs) by strong oxidants such as potassium permanganate (KMnO4) has been proposed as a possible DNAPL remediation strategy. In this study, we investigated the effects of in-situ trichloroethene (TCE) oxidation by KMnO4 on porous medium hydraulic properties. In particular, we wanted to determine the overall effects of concurrent solid phase (MnO2) precipitation, gas (CO2) evolution and TCE dissolution resulting from the oxidation reaction on the porous medium's aqueous-phase relative permeability, krw. Three TCE removal experiments were conducted in a 95-cm long, 5.1-cm i.d. glass column, which was homogeneously packed with well-characterized 30/40-mesh silica sand. TCE was emplaced in the sand-pack in residual, entrapped form through a sequence of water/TCE imbibition and drainage steps. The column was then flushed under constant aqueous flux conditions for up to 104 h with either deionized water (reference experiment), deionized water containing 5 mM KMnO4 or deionized water containing 5 mM KMnO4 and 300 mM Na2HPO4. Aqueous-phase relative permeabilities were computed from measured flow rates and measurements of aqueous-phase pressure head, h obtained using pressure transducers connected to tensiometers distributed along the column length. A dual-energy gamma radiation system was used to monitor changes in fluid saturation that occurred during each experiment. In addition, column effluent samples were collected for chemical analyses. Dissolution of TCE during deionized water flushing led to an increase in krw by approximately 22% and a local reduction in h. On the other hand, vigorous CO2 gas production and precipitation of MnO2 was visually observed during flushing with deionized water that contained 5 mM KMnO4. As a consequence, krw declined by approximately 96% and h increased locally by more than 1000 cm H2O during the first 24 h of the experiment, causing sand-pack ruptures and pump failure. Conversely, less CO2 gas production and MnO2 precipitation was visually observed during flushing with deionized water that contained 5 mM KMnO4 and 300 mM Na2HPO4. Consequently, only small increases in h (< 15 cm H2O) were observed in this experiment due to a reduction in krw of approximately 53%. While we must attribute changes in h due to variations in krw to our specific experimental design (constant aqueous flux, one-dimensional flow experiments), these experiments nevertheless confirm that successful application of in situ chemical oxidation of TCE requires consideration of detrimental processes such as MnO2 precipitation and CO2 gas formation. In addition, our results indicate that utilization of a buffered oxidant solution may improve the effectiveness of in-situ oxidation of TCE by KMnO4 in otherwise weakly buffered porous media.

Apical localization of the coxsackie-adenovirus receptor by glycosyl-phosphatidylinositol modification is sufficient for adenovirus-mediated gene transfer through the apical surface of human airway epithelia.

In well-differentiated human airway epithelia, the coxsackie B and adenovirus type 2 and 5 receptor (CAR) resides primarily on the basolateral membrane. This location may explain the observation that gene transfer is inefficient when adenovirus vectors are applied to the apical surface. To further test this hypothesis and to investigate requirements and barriers to apical gene transfer to differentiated human airway epithelia, we expressed CAR in which the transmembrane and cytoplasmic tail were replaced by a glycosyl-phosphatidylinositol (GPI) anchor (GPI-CAR). As controls, we expressed wild-type CAR and CAR lacking the cytoplasmic domain (Tailless-CAR). All three constructs enhanced gene transfer with similar efficiencies in fibroblasts. In airway epithelia, GPI-CAR localized specifically to the apical membrane, where it bound adenovirus and enhanced gene transfer to levels obtained when vector was applied to the basolateral membrane. Moreover, GPI-CAR facilitated gene transfer of the cystic fibrosis transmembrane conductance regulator to cystic fibrosis airway epithelia, correcting the Cl(-) transport defect. In contrast, when we expressed wild-type CAR it localized to the basolateral membrane and failed to increase apical gene transfer. Only a small amount of Tailless-CAR resided in the apical membrane, and the effects on apical virus binding and gene transfer were minimal. These data indicate that binding of adenovirus to an apical membrane receptor is sufficient to mediate effective gene transfer to human airway epithelia and that the cytoplasmic domain of CAR is not required for this process. The results suggest that targeting apical receptors in differentiated airway epithelia may be sufficient for gene transfer in the genetic disease cystic fibrosis.

In situ determination of subsurface microbial enzyme kinetics.

The single-well, push-pull test has been used in previous field studies to measure in situ zero- and first-order rates for aerobic and anaerobic microbial respiration in the saturated zone. In this paper we demonstrate that the test can also be used to obtain more generalized descriptions of the kinetics of microbially mediated enzymatic reactions. Laboratory and field tests were performed with the model enzyme substrate p-nitrophenyl-beta-D-glucopyranoside (PNG). During a push-pull test, injected PNG is hydrolyzed in situ to p-nitrophenol (PNP); the rate of PNP production is taken as a measure of the beta-glucosidase activity expressed by indigenous microorganisms. Laboratory tests were performed in physical aquifer models packed with natural aquifer sediment; field tests were performed in a shallow unconfined alluvial aquifer at a petroleum contaminated site. The laboratory and field tests demonstrate that it is possible to compute the in situ rate of PNP production as a function of PNG concentration using only data from a single push-pull test. These data can then be used to estimate the Michaelis-Menton kinetic parameters Vmax and Km for the hydrolysis reaction. This approach potentially extends the range of applicability of the push-pull test approach for use in determining kinetic parameters for a wide range of microbial processes in situ. These could include the broad class of substituted nitrophenyl substrates used to assay other enzyme systems, as well as microbially mediated redox reactions that occur during contaminant transformations.

The effects of type and amount of pretraining on transfer in concept formation.

Two experiments were conducted to investigate the effects of 2 types of directed attention pretraining, a form of stimulus predifferentiation, on immediate- and delayed-transfer tasks in concept identification. In both experiments, the participants received either the "seeing-and-discriminating" or "seeing" technique of pretraining, except for those assigned to the control group. The participants received different amounts of pretraining. In the first experiment, participants were required to learn new concepts from the same category for the delayed-transfer task, whereas in the second experiment, the delayed-transfer task involved concepts from a different category. Among the major findings in both experiments are that the pretraining methods resulted in positive transfer on all transfer tasks. In general, the seeing-and-discriminating method yielded a more positive transfer than the seeing technique. Maximal positive transfer effects were found with a small number of trials. The implications of the findings for understanding the effectiveness of various training methods used for problem solving are discussed.